The closely matched Polymarket bins around 2.65M–2.95M votes reflect trader consensus on expected turnout for the 2026 Massachusetts U.S. Senate election in a low-competition general election. Incumbent Democrat Ed Markey holds a consistent 25–30 point lead over Republican John Deaton in recent polling, producing limited enthusiasm after a lopsided Democratic primary against Seth Moulton. This dynamic aligns with historical midterm patterns in safely Democratic states, where participation typically falls well below presidential-year levels. Early in-person and mail ballot returns near 500,000 as of late October provide a baseline, while typical drop-off, weather on Election Day, and the volume of ballot questions continue to shape assessments without recent catalysts creating separation among the leading ranges.